Electrical devices have been used in the prior art to treat pain or other symptoms by the application of energy in the form of alternating current electricity, direct current, magnetism and other forms of electromagnetic energy. As used herein, the adjective electrical, as in electrical energy, is intended to be generic to these different types of energy. One well accepted technique is known as electrical interferential therapy in which electrodes are connected in a crossing pattern adjacent the area to be treated. Alternating current is delivered through the electrodes into the body. One such device is commercially available from Dynatronics, Inc. of Salt Lake City, Utah. In the past, this type equipment has been used to treat small areas of the body because the electrodes are spaced relatively close together in the region to be treated. An electrical interferential device provides a carrier frequency and a second frequency that is only a few Hertz from the carrier frequency to produce a beat frequency which is the difference between the two. In most modern interference devices, the carrier frequency is fixed and the beat frequency can be adjusted slightly, e.g. over a range of 1-200 Hz, to provide different therapeutic results. In the past, these adjustments were made by the care provider in response to answers or reactions from the patient.
A promising interferential treatment is disclosed in U.S. Pat. No. 5,995,873, the disclosure of which is incorporated herein by reference. In this disclosure, two interferential devices are attached to a patient so the electrical signals travel along different nerve pathways to, around and away from the spinal column to treat pain and/or a variety of ailments, most of which involve some aspect of the sympathetic nervous system. The disclosure of this patent is extended in co-pending application Ser. No. 11/326,230, filed Jan. 5, 2006, the disclosure of which is also incorporated herein by reference.
Other disclosures of interest are found in U.S. Pat. Nos. 6,047,011; 6,126,183; 6,212,427 and 6,305,943.